Though sweet potatoes aren’t any better for your waistline than normal white potatoes, they do have a different taste and can help make a difference to a boring meal. One problem when substituting normal potatoes with sweet potatoes when you make fries with them is that they don’t get crispy or crunchy, they just end up soggy and limp, whether you fry or oven bake them. I looked into the problem of why you can’t get crunchy sweet potato fries and found a few options to try and get better results.
The first method suggested soaking them in water for a few hours, drying them and then baking them. Another suggested blanching them in boiling water for a minute or so, stopping them cooking with iced water, drying them and then baking them. A third method suggested tossing the sweet potato fries in corn starch (corn flour), then baking them. In the interest of science, I tried all three methods to determine what works the best.
Method 1: Soaking the sweet potatoes in water
This method is meant to help draw out starches from the sweet potatoes fries in the same way that this helps when making French Fries with normal potatoes. Peel and chop the sweet potatoes into batons. Place them in a bowl, cover with cold water and leave to soak for a couple of hours. Drain the sweet potatoes and allow them to dry. Place on a lightly oil baking sheet, drizzle with a little oil and place in a 450F (230C) oven for 15 to 20 mins until brown.
Method 2: Blanching the sweet potatoes
This method also follows a technique used with normal French Fries. Prepare the sweet potatoes fries and place into boiling water for 2 to 3 minutes. Remove the sweet potato fries and plunge into iced water to prevent further cooking. Drain the fries, and allow them to dry. Place on a lightly oil baking sheet, drizzle with a little oil and place in a 450F (230C) oven for 15 to 20 mins until brown.
Method 3: Coating the sweet potatoes in corn starch
This method forgets about try to create a crispy sweet potato fry and creates a coating to become crispy. As before, prepare the sweet potato batons. Place some corn starch into a plastic bag, add a few sweet potato fries into the bag and shake the bag to coat each of them with corn starch. Remove the fries from the bag, and as before place on a lightly oil baking sheet, drizzle with a little oil and place in a 450F (230C) oven for 15 to 20 mins until brown.
Now which method worked the best? Well soaking in water, didn’t make any difference for me. I really made sure that the fries were dry before cooking them, but they seemed to end up soggier than normal. Blanching, or par-cooking the sweet potatoes beforehand worked slightly better than normal, but the clear winner was coating the sweet potato fries in corn starch before cooking.
One thing to note when baking sweet potato fries in the oven is not to crowd them. Give them room to breathe and get rid of as much water as possible.